1. Field of the Invention
The present invention relates to a composite electronic component including a plurality of electronic elements.
2. Description of the Related Art
Conventionally, several inventions have been proposed regarding a composite electronic component having multiple electronic elements from the view point of high integration of electronic components on a wiring substrate.
For example, JP-A 2001-338838 discloses a composite electronic component consisting of a capacitor and a resistor. In this composite electronic component, the resistor is disposed on the surface of a capacitor body of a chip capacitor, and the resistor and a pair of external electrodes disposed on the surface of the capacitor body are connected with each other.
JP-A 6-283301 discloses a composite electronic component in which two or more rectangular parallelepiped chip elements having the same shape and the same dimension selected from the group consisting of a chip resistance, a chip thermistor, a chip capacitor and a chip varistor are overlapped one another in the thickness direction of these, and terminal electrodes provided in these are collectively covered with a lead frame to integrate the same.
The inventors proposed in Japanese Patent Application No. 2015-049457 (U.S. patent application Ser. No. 15/042,236) a composite electronic component capable of improving the degree of freedom in circuit design compared with those disclosed in JP-A 6-283301 and Japanese Patent Application No. 2015-049457 (U.S. patent application Ser. No. 15/042,236). The composite electronic component is a composite electronic component having a novel constitution in which to one substrate-type electronic element formed of an insulating base member and imparted with a function of a passive element, other one electronic element is joined.
In the composite electronic component having the novel constitution as described above, the upper surface of the insulating base member of the substrate-type electronic element faces the other one electronic element. The upper surface is provided with an upper surface conductor to which other one electronic element is connected via a joint material. In one mode of the composite electronic component having a novel constitution, on the upper surface of the insulating base member of the substrate-type electronic element, another upper surface conductor that is connected with an electric functional part contained in the substrate-type electronic element is also disposed in addition to the upper surface conductor.
These upper surface conductors generally contain a conductive layer formed of Ag or Cu so as to obtain sufficient conductivity. However, Ag and Cu are conductive materials that easily cause to a so-called “ion migration”, the problem that under the application of an electric field, they partly ionize and migrate to other position, and after the migration, they are reduced and precipitated again.
For this reason, when such an upper surface conductor as in the composite electronic component having a novel constitution is used without taking any measures against the problem of ion migration, insulation resistance between the upper surface conductors can be deteriorated.